It seems like it would be more effective to simply put all the solar panels in a field, and construct a cheap shade over the entire canal no? The supports in the picture are massive and don't look cheap. Also I would imagine the solar array uses more copper than a similar capacity array just built in a field. You can't daisy chain multiple miles of solar panels together, so you need an extra power line to run alongside the whole thing.
Put the solar panels in a field: The solar array uses less copper.
The shade supports don't have to hold up solar panels: Shade supports cost less.
The best reasoning they give is that California has insane permitting requirements, and it takes 1/6 the time to build on developed land compared to undeveloped land.
Anecdotally speaking, I have heard of a massive California solar farm in an undeveloped area that has serious vandalism problems. Junkies will find ways through the fencing at night, strip copper and other materials from panels, and cause thousands in damages and lost energy just to extract enough scrap for a fix.
Nothing short of a face-to-face security response will deter these criminals, so there it is a challenging cost-benefit balance. At least panels in parking lots and other developed spaces have the benefit of witnesses. I'm sure a 20 foot climb up a steel beam over running water is a decent deterrent as well.
> It seems like it would be more effective to simply put all the solar panels in a field, and construct a cheap shade over the entire canal no?
No because now you're using land that could be used for other things, which is exactly what this avoids. This takes existing land that loses water and costs money, and makes it lose less water and make money.
You are assuming that land is expensive and forgetting that building and maintaining panels over long a canal is harder than building over a large plot.
My understanding is that "The best reasoning they give" is the entire point. It such a huge issue that it drowns out all of the valid but smaller issues you are pointing out. And, the benefit to the water is just a bonus.
The cost of building that steel structure that will hold up against maximum in 100 year wind forces isn't cheap. Large PV panels make very good sails. The trusses look basically the same as you'd see in a large agricultural barn, horse riding arena, etc. Putting the PV panels on empty bare land at a height people can walk around and work with would be considerably less costly.
I would very much like to see a total dollar figure for the example "roof trusses over the canel" structure vs. how many panels it can hold.
It's already true that the ground mounting costs and labor to assemble the ground mount are a huge part of building a large scale PV system.
> Putting the PV panels on empty bare land at a height people can walk around and work with would be considerably less costly.
What empty, bare land?
If its really empty and bare, there is a reason for it and that reason is probably a problem for building and maintaining PV, and otherwise you have to add the loss of the alternative uses of the land to the cost.
In the context of California, land that is not suitable for agriculture because it can't be irrigated, even though it's flat and somewhat accessible by road. California has plenty of it, go drive around near Twenty Nine Palms and you'll see it...
To my eye if you were putting up a few hundred or more of those steel structures, and it didn't require a redesign of the canal retainment around it, it could be built quite economically.
Every extra pylon structure built, especially the first dozen, will be cheaper and easy to produce and install.
How about hanging solar panel vertically on tall buildings covering every floor except the first few to prevent vandalism
As the earth moves the sun would only hit one side and lose efficiency but right now it's "free space" not being used otherwise
They even make flexible solar panels now that can bend and move with the wind and don't need a stiff frame, slightly less efficient but volume makes up for that
Clean them the same way automated window washers work on skyscrapers
Shame they never came up with the solar paint solution, yet
The best explanation I've heard is from a PV installer. He said, "Every try to get a suntan standing up?" Seems you lose too much sun exposure to make it worthwhile.
I didn't try to get a suntan, but I have gotten tans while standing up. It's called working outdoors (and not properly covering up, which I'm paying for now).
That said, the economics of vertical installations have changed. The cost of panels keep going down, and as they do it's starting to make sense depending on your location and how you're orienting your vertical panels. Remember, almost all solar panel installations will be suboptimal unless they include a mechanism for tracking the sun. The question is how bad is suboptimal, what's the cost of the panels and what's their energy yield?
What's the lifetime of a "cheap shade"? And the cost to renew it over the same lifetime? And the cost of paying for other land?
... likely less than the ~$13/W this cost to install, but that included NRE for three different styles of panel mounting. Standardizing would cut costs significantly.
Yes, I'd like to see the "cheap shade" that could span as far as shown in the pics as well as survive strong gales. It wouldn't be like a cheap shade in your back yard.
I'm sure it could be done, but it would cost a fortune. My understanding is the canals were built to distribute water to farmers, and conservation/evaporation wasn't really much of a consideration because California had plenty of water back then.
BTW, I used to swim in those same canals around Modesto and Turlock as a kid. So gross.
>It seems like it would be more effective to simply put all the solar panels in a field, and construct a cheap shade over the entire canal no?
Yes, absolutely. But if you try and do that kind of stuff and the regulators show up and kick you right in the dick. "You got a permit to put panels this land?" "Where's your environmental impact assessment for shading that canal?". And HN cheers.
But if you say you want to cover the canal with solar panels out comes the rubber stamp because that's what the powers that be want to "incentivize" this week.
Does the success of populists make a little more sense now?
There are solutions like this to most of Californias big intractable problems, and they're not done because some California laws and/or regulations make it impossible.
This is one reason I now live in Nevada, where pretty much everything is legal...
I seriously doubt that you can chain even 1/4 mile of panels together without destroying things. Thats already puting thousands of volts and hundreds or thousands of amps through the silicon. If you are making it all parallel you still need wiring between panels that can handle that. The cabling doesn't go away, it just moves.
Wouldn't there still be supports in a feild of solar panels? Are you sure that those supports + the supports for the shade material are going to be less material than the supports for this?
Most shade material wears out pretty quickly. Will their replacement result in more expense, more waste, etc than just putting the solar panels?
Shade material is generally pretty heavy, is it really going to need significantly less robust support? Weight aside, how much of the load those supports are rated for is due to the actual weight of the panels, and how much is for forces from things like wind?
"Thats already puting thousands of volts and hundreds or thousands of amps through the silicon."
In a typical string of solar panels design, you'll get tons of volts but not a lot in amps - current cell maximums top out at ~11A and the connective MC4 wiring can't handle too much more current than that, so what you end up with is like a 1,000V 10A string on one MPPT connection into the inverter.
A solar panel is 4 feet or so on the long side. Theres 250+ of them in a string 1/4 mile long.... at 48 V/panel, you get to 12KV. even if it's topped out at 10A thats still 120KW... you need a hefty cable to carry that panel to panel. Which is the core of the point I was making.
Amps determine how hefty a cable needs to be, not volts. Volts mostly determine how thick the insulation needs to be.
14 gauge wire is basically all you need to carry 10A safely for an extended period of time regardless the voltage. It doesn't matter that you are carrying 120KW.
The proof of this is in EV charge cables. Those bad boys can carry up to 350kW. Yet the cables are often thinner than you might expect. How do they do this? It's by using high voltages (around 900V) which cuts back the amps to around 300->400.
Tesla's chargers peak (or used to) around 600V which has required them to have much beefier cables to handle the high current.
Maybe, but ideas like that are what you all will use to eventually turn against solar and seek to ban going off grid as you see a disparity between those who can afford to buy solar and those who can't. Why's that a problem? Those who can will go off grid and those who can't will be left on a grid that they can't pay for, and it will crumble. We are already seeing the beginnings of this in California.
When you read lines like "California’s extensive network of canals and aqueducts is the lifeblood of the state, providing clean water to populous cities and expansive farms that wouldn’t otherwise have it." you have to ask how we ended up with these canal systems, what the tradeoffs are in a landscape setup this way rather than one where water infiltrates the ground and stays hydrated, and who owns water rights in California.
(note: I'm not trying to totally bash the solar panel project nor some of the key figures involved who've done great work like Dustin Mulvaney, but do think we should think about how we ended up here)
I thought this was a pretty awesome video to provide the lore on how water got to Southern California. Growing up in Pasadena I heard the name Mulholland and Eaton (as in canyon) all the time but never realized they were so instrumental in the founding of the city and all the wild shenanigans that went into getting the water from up north to LA.
In searching YouTube history for it, I see I also stumbled across this project too: Why Aqueduct Solar Solves 2 MASSIVE Problems https://youtu.be/EVBacmPfQ6E (about 9 minutes in it gets into the engineering challenges mentioned else comment about wind loads and such).
oof, that is a crap ton of steel. I doubt those panels will ever harvest enough energy to offset the energy use to produce both the cells and supports.
I imagine with cells in that configuration, lifting wind loads are significant which is why it's overbuilt like that.
Perhaps some laminate timber for the cross supports?
Lastly, the US has got to start eating seasonally. The water problem in the southwest is all agriculture: people want to grow baby spinach in January. Unless we figure out a way to create a crap ton of energy cheaply so we can supply industrial sized flows without worrying about the energy cost, we use far more water than we should in California and Arizona.
Electricity is incidental (and a nice benefit) to the goal of "reduce evaporation of water from the irrigation canal and improve water quality".
> The duo went on to start Solar Aquagrid, an advocacy firm dedicated to reimagining aging canals, and partnered with the Turlock Irrigation District, UC Merced and the California Department of Water Resources to cover small sections of Turlock’s canals with solar panels. The new “solar canal” provides shade to limit evaporation and generates power all in one neat package. They call it Project Nexus, and it operates at the intersection of the state’s need for clean water and energy.
> ...
> But the canal site hosts more than just panels. Bales said they “have instruments out there to measure temperature, relative humidity, wind speed, incoming radiation, outgoing radiation, and a prototype instrument to measure evaporation directly.”
> When it comes to algae, the panels helped. “Last year when we drained the canal at the end of the irrigation season, there was a physical line on the sun side of the canal that had algae growth and then not algae growth from where the shade was,” Weimer said.
That it's green energy and can help supply the power demand is a bonus.
Steel takes about 4.750 kw-hours to produce per kg.[1]
A 450W solar panel will make roughly 562 kwh a year in California.[2]
So one panel running for one year offsets 140kg of steel production, roughly.
Thats an I-beam based structure so it's weight efficient and a heck of a lot more then 1 solar panel are going to fit on it.
Judging from a local steel supplier[3] and some span tables it looks like you'd need about a 360mm or so I-beam to bridge a 115 ft (30m) channel (the structure looks more efficient then that though) so call it 50kg per meter. So one span is probably ballpark 1500kg of steel.
A 450W solar panel is about 0.7m wide, the structure is fully covered so call it 42 panels per span offsetting the energy production of a little over 5900kg of steel per year (and it doesn't look like we're putting one solid I-beam per row of solar panels either since I see lightweight spanning channel in there).
According to my searches, steel production is something like 6-8 MWh/ton to extract, refine, and shape. A solar panel lasts 25 years at up to 80% effiency. This thing produces 1.7MW at peak. so call it 3 MWh/day average to account for a lot of adverse conditions over the lifetime. Thats 27000 MWh... so unless we are looking at more than 3000 tons of steel (we aren't) the steel production is accounted for. A panel takes something like 1.9 MWh equivalent in energy.... and again we aren't looking at 13K solar panels in this pilot.
So yes, in fact this does generate far more energy than goes into its production.
It seems like it would be more effective to simply put all the solar panels in a field, and construct a cheap shade over the entire canal no? The supports in the picture are massive and don't look cheap. Also I would imagine the solar array uses more copper than a similar capacity array just built in a field. You can't daisy chain multiple miles of solar panels together, so you need an extra power line to run alongside the whole thing.
Put the solar panels in a field: The solar array uses less copper. The shade supports don't have to hold up solar panels: Shade supports cost less.
The best reasoning they give is that California has insane permitting requirements, and it takes 1/6 the time to build on developed land compared to undeveloped land.
Anecdotally speaking, I have heard of a massive California solar farm in an undeveloped area that has serious vandalism problems. Junkies will find ways through the fencing at night, strip copper and other materials from panels, and cause thousands in damages and lost energy just to extract enough scrap for a fix.
Nothing short of a face-to-face security response will deter these criminals, so there it is a challenging cost-benefit balance. At least panels in parking lots and other developed spaces have the benefit of witnesses. I'm sure a 20 foot climb up a steel beam over running water is a decent deterrent as well.
And the one thing California absolutely will not do is put these people in jail.
> It seems like it would be more effective to simply put all the solar panels in a field, and construct a cheap shade over the entire canal no?
No because now you're using land that could be used for other things, which is exactly what this avoids. This takes existing land that loses water and costs money, and makes it lose less water and make money.
That’s true of everything you build. The cost of land has to be taken into account, but land is much cheaper in some areas than others.
You are assuming that land is expensive and forgetting that building and maintaining panels over long a canal is harder than building over a large plot.
My understanding is that "The best reasoning they give" is the entire point. It such a huge issue that it drowns out all of the valid but smaller issues you are pointing out. And, the benefit to the water is just a bonus.
Exactly, that is hundreds of miles over which no NIMBY holds sway. The state can do what they want.
The cost of building that steel structure that will hold up against maximum in 100 year wind forces isn't cheap. Large PV panels make very good sails. The trusses look basically the same as you'd see in a large agricultural barn, horse riding arena, etc. Putting the PV panels on empty bare land at a height people can walk around and work with would be considerably less costly.
I would very much like to see a total dollar figure for the example "roof trusses over the canel" structure vs. how many panels it can hold.
It's already true that the ground mounting costs and labor to assemble the ground mount are a huge part of building a large scale PV system.
> Putting the PV panels on empty bare land at a height people can walk around and work with would be considerably less costly.
What empty, bare land?
If its really empty and bare, there is a reason for it and that reason is probably a problem for building and maintaining PV, and otherwise you have to add the loss of the alternative uses of the land to the cost.
In the context of California, land that is not suitable for agriculture because it can't be irrigated, even though it's flat and somewhat accessible by road. California has plenty of it, go drive around near Twenty Nine Palms and you'll see it...
> What empty, bare land?
Have you been to Death Valley, my friend? All of Southeastern California is empty, barren land. Death Valley, Mojave Desert, etc.
To my eye if you were putting up a few hundred or more of those steel structures, and it didn't require a redesign of the canal retainment around it, it could be built quite economically.
Every extra pylon structure built, especially the first dozen, will be cheaper and easy to produce and install.
How about hanging solar panel vertically on tall buildings covering every floor except the first few to prevent vandalism
As the earth moves the sun would only hit one side and lose efficiency but right now it's "free space" not being used otherwise
They even make flexible solar panels now that can bend and move with the wind and don't need a stiff frame, slightly less efficient but volume makes up for that
Clean them the same way automated window washers work on skyscrapers
Shame they never came up with the solar paint solution, yet
> How about hanging solar panel vertically
The best explanation I've heard is from a PV installer. He said, "Every try to get a suntan standing up?" Seems you lose too much sun exposure to make it worthwhile.
> "Every try to get a suntan standing up?"
I didn't try to get a suntan, but I have gotten tans while standing up. It's called working outdoors (and not properly covering up, which I'm paying for now).
That said, the economics of vertical installations have changed. The cost of panels keep going down, and as they do it's starting to make sense depending on your location and how you're orienting your vertical panels. Remember, almost all solar panel installations will be suboptimal unless they include a mechanism for tracking the sun. The question is how bad is suboptimal, what's the cost of the panels and what's their energy yield?
I've got many a sun burn standing as has anyone else who's toiled away outdoors doing something while shirtless and white...
I suspect it's more of a "hassle ain't worth it to lose 20%" type situation.
Could absolutely be worth if you can make that 20% back dodging permits because it's not flagrantly visible on the aerials like roof panels are.
What's the lifetime of a "cheap shade"? And the cost to renew it over the same lifetime? And the cost of paying for other land?
... likely less than the ~$13/W this cost to install, but that included NRE for three different styles of panel mounting. Standardizing would cut costs significantly.
Yes, I'd like to see the "cheap shade" that could span as far as shown in the pics as well as survive strong gales. It wouldn't be like a cheap shade in your back yard.
Or better yet, invest in pipes.
Canal sized pipes?
I'm pretty sure those are called tunnels
I'm sure it could be done, but it would cost a fortune. My understanding is the canals were built to distribute water to farmers, and conservation/evaporation wasn't really much of a consideration because California had plenty of water back then.
BTW, I used to swim in those same canals around Modesto and Turlock as a kid. So gross.
At least $16 billion for 45 miles. See https://www.deltaconveyanceproject.com/about-the-delta-conve... and https://en.wikipedia.org/wiki/Delta_Conveyance_Project
According to AI, that pipe would only need to be 43 Feet in diameter, only 43 feet wide. Pretty sure they have that at Home Depot.
>It seems like it would be more effective to simply put all the solar panels in a field, and construct a cheap shade over the entire canal no?
Yes, absolutely. But if you try and do that kind of stuff and the regulators show up and kick you right in the dick. "You got a permit to put panels this land?" "Where's your environmental impact assessment for shading that canal?". And HN cheers.
But if you say you want to cover the canal with solar panels out comes the rubber stamp because that's what the powers that be want to "incentivize" this week.
Does the success of populists make a little more sense now?
There are solutions like this to most of Californias big intractable problems, and they're not done because some California laws and/or regulations make it impossible.
This is one reason I now live in Nevada, where pretty much everything is legal...
A lot of things get easier when everyone basically lives in one city, yes.
Power lines are made of aluminum and steel.
I seriously doubt that you can chain even 1/4 mile of panels together without destroying things. Thats already puting thousands of volts and hundreds or thousands of amps through the silicon. If you are making it all parallel you still need wiring between panels that can handle that. The cabling doesn't go away, it just moves.
Wouldn't there still be supports in a feild of solar panels? Are you sure that those supports + the supports for the shade material are going to be less material than the supports for this?
Most shade material wears out pretty quickly. Will their replacement result in more expense, more waste, etc than just putting the solar panels?
Shade material is generally pretty heavy, is it really going to need significantly less robust support? Weight aside, how much of the load those supports are rated for is due to the actual weight of the panels, and how much is for forces from things like wind?
"Thats already puting thousands of volts and hundreds or thousands of amps through the silicon."
In a typical string of solar panels design, you'll get tons of volts but not a lot in amps - current cell maximums top out at ~11A and the connective MC4 wiring can't handle too much more current than that, so what you end up with is like a 1,000V 10A string on one MPPT connection into the inverter.
A solar panel is 4 feet or so on the long side. Theres 250+ of them in a string 1/4 mile long.... at 48 V/panel, you get to 12KV. even if it's topped out at 10A thats still 120KW... you need a hefty cable to carry that panel to panel. Which is the core of the point I was making.
Amps determine how hefty a cable needs to be, not volts. Volts mostly determine how thick the insulation needs to be.
14 gauge wire is basically all you need to carry 10A safely for an extended period of time regardless the voltage. It doesn't matter that you are carrying 120KW.
The proof of this is in EV charge cables. Those bad boys can carry up to 350kW. Yet the cables are often thinner than you might expect. How do they do this? It's by using high voltages (around 900V) which cuts back the amps to around 300->400.
Tesla's chargers peak (or used to) around 600V which has required them to have much beefier cables to handle the high current.
>>The state currently generates 62% of its electricity from renewable and zero-carbon sources, with the largest percentage of that coming from solar
62% is pretty respectable for the size of California (same electricity consumption as Spain). I did not know this.
They should give credit where credit is due. Solar panels on top of irrigation canals was pioneered in the Indian state of Gujarat back in 2012[1]
[1] https://www.autonocion.com/us/arizona-solar-panels-irrigatio...
You need to credit someone for "hey lets use solar panels to shade things that would benefit from shade"?
They don't mention Gujarat specifically, but they do mention the prior projects in India and Arizona (which your link discusses) in the article.
Are there risks of any poisons or chemicals from the solar panels leaking into the water system over time?
This hacker entered the thread thinking this was a good idea but leaves muttering “man, things are complicated.”
Maybe, but ideas like that are what you all will use to eventually turn against solar and seek to ban going off grid as you see a disparity between those who can afford to buy solar and those who can't. Why's that a problem? Those who can will go off grid and those who can't will be left on a grid that they can't pay for, and it will crumble. We are already seeing the beginnings of this in California.
When you read lines like "California’s extensive network of canals and aqueducts is the lifeblood of the state, providing clean water to populous cities and expansive farms that wouldn’t otherwise have it." you have to ask how we ended up with these canal systems, what the tradeoffs are in a landscape setup this way rather than one where water infiltrates the ground and stays hydrated, and who owns water rights in California.
Build Soil has some interesting threads on this:
- https://bsky.app/profile/buildsoil.bsky.social/post/3lmeddjd...
- https://bsky.app/profile/buildsoil.bsky.social/post/3mkzybkk...
(note: I'm not trying to totally bash the solar panel project nor some of the key figures involved who've done great work like Dustin Mulvaney, but do think we should think about how we ended up here)
Back when they thought they could pay their way out of problems. Looking at you florida everglades
I thought this was a pretty awesome video to provide the lore on how water got to Southern California. Growing up in Pasadena I heard the name Mulholland and Eaton (as in canyon) all the time but never realized they were so instrumental in the founding of the city and all the wild shenanigans that went into getting the water from up north to LA.
https://www.youtube.com/watch?v=x-RGL15Skuo
There's also a practical engineering video on it: The Los Angeles Aqueduct is Wild https://www.youtube.com/watch?v=PhW2BjFQCZM ( https://practical.engineering/blog/2026/3/17/the-los-angeles... for blog post transcript)
In searching YouTube history for it, I see I also stumbled across this project too: Why Aqueduct Solar Solves 2 MASSIVE Problems https://youtu.be/EVBacmPfQ6E (about 9 minutes in it gets into the engineering challenges mentioned else comment about wind loads and such).
oof, that is a crap ton of steel. I doubt those panels will ever harvest enough energy to offset the energy use to produce both the cells and supports.
I imagine with cells in that configuration, lifting wind loads are significant which is why it's overbuilt like that.
Perhaps some laminate timber for the cross supports?
Lastly, the US has got to start eating seasonally. The water problem in the southwest is all agriculture: people want to grow baby spinach in January. Unless we figure out a way to create a crap ton of energy cheaply so we can supply industrial sized flows without worrying about the energy cost, we use far more water than we should in California and Arizona.
Electricity is incidental (and a nice benefit) to the goal of "reduce evaporation of water from the irrigation canal and improve water quality".
> The duo went on to start Solar Aquagrid, an advocacy firm dedicated to reimagining aging canals, and partnered with the Turlock Irrigation District, UC Merced and the California Department of Water Resources to cover small sections of Turlock’s canals with solar panels. The new “solar canal” provides shade to limit evaporation and generates power all in one neat package. They call it Project Nexus, and it operates at the intersection of the state’s need for clean water and energy.
> ...
> But the canal site hosts more than just panels. Bales said they “have instruments out there to measure temperature, relative humidity, wind speed, incoming radiation, outgoing radiation, and a prototype instrument to measure evaporation directly.”
> When it comes to algae, the panels helped. “Last year when we drained the canal at the end of the irrigation season, there was a physical line on the sun side of the canal that had algae growth and then not algae growth from where the shade was,” Weimer said.
That it's green energy and can help supply the power demand is a bonus.
> Lastly, the US has got to start eating seasonally.
Fair. But the almonds and alfalfa would like a word, especially since the alfalfa is shipped around the world for others to consume in some way.
So while it's definitely agriculture as a serious source, it's not just the US as the driver of that source.
Steel takes about 4.750 kw-hours to produce per kg.[1]
A 450W solar panel will make roughly 562 kwh a year in California.[2]
So one panel running for one year offsets 140kg of steel production, roughly.
Thats an I-beam based structure so it's weight efficient and a heck of a lot more then 1 solar panel are going to fit on it.
Judging from a local steel supplier[3] and some span tables it looks like you'd need about a 360mm or so I-beam to bridge a 115 ft (30m) channel (the structure looks more efficient then that though) so call it 50kg per meter. So one span is probably ballpark 1500kg of steel.
A 450W solar panel is about 0.7m wide, the structure is fully covered so call it 42 panels per span offsetting the energy production of a little over 5900kg of steel per year (and it doesn't look like we're putting one solid I-beam per row of solar panels either since I see lightweight spanning channel in there).
[1] https://solar.lowtechmagazine.com/2009/06/how-much-energy-do...
[2] https://www.cahomesolar.com/feeds/blog/solar-panel-energy-pr...
[3] https://www.mascotsteel.com.au/wp-content/uploads/2018/10/st...
> I doubt those panels will ever harvest enough energy to offset the energy use to produce both the cells and supports.
While I agree those steel supports are large, that seems insanely wrong to me, but not an expert so curious if someone with more info could comment.
According to my searches, steel production is something like 6-8 MWh/ton to extract, refine, and shape. A solar panel lasts 25 years at up to 80% effiency. This thing produces 1.7MW at peak. so call it 3 MWh/day average to account for a lot of adverse conditions over the lifetime. Thats 27000 MWh... so unless we are looking at more than 3000 tons of steel (we aren't) the steel production is accounted for. A panel takes something like 1.9 MWh equivalent in energy.... and again we aren't looking at 13K solar panels in this pilot.
So yes, in fact this does generate far more energy than goes into its production.
What is it learning?